1. Field of the Invention
The present invention relates to devices for rotating drill shafts and, more particularly, is directed towards devices for applying torque and thrust to flexible roof drills.
2. Description of the Prior Art
In the mining industry, falls of mine roofs account for a large percentage of the fatalities that occur in coal mines. Thus, roof control has been a major safety and production consideration. Roof fall fatalities have been greatly reduced in cases where the mine roof is supported with roof bolts that are inserted into holes which are drilled into the mine roof using a drill that is attached to a rigid shaft. As the holes become progressively deeper, the mine worker adds extension sections to the drill shaft. Such an operation requires the worker to be at the head of a roof drilling machine for starting the hole, for adding the extension sections and for inserting the bolts. In this hazardous position, the operator is exposed to both roof falls and the exposed rotating drill shaft.
Flexible roof drills eliminate the need for adding extension section and allow the operator to drill holes longer-than-the-seam height continuously and remotely. Machines that have been developed for applying torque and thrust to flexible roof drills have been met with varying degrees of success due to the height and the high hydraulic pressure requirements of such machines. A need has arisen for a reliable and simple machine for applying torque and thrust to flexible shaft roof drills.